Method for treating a sphincter

ABSTRACT

A method for treating a sphincter provides a polymer material having a liquid state. The method also provides a catheter having a distal end, a tissue piercing device carried by the distal end, and an energy delivery device coupled to the tissue piercing device. The tissue piercing device has a lumen. The method introduces the catheter into an esophagus and pierces an exterior sphincter tissue surface within with the tissue piercing device. The method advances the tissue piercing device into an interior sphincter tissue site and conveys the polymer material while in a liquid state through the lumen into the interior sphincter tissue site. The method delivers energy to the tissue piercing device to transform the polymer material into a less liquid state within the interior sphincter tissue site, to thereby remodel the sphincter.

RELATED APPLICATIONS

[0001] This application is a continuation of co-pending U.S. patentapplication Ser. No. 09/090,794, filed Jun. 4, 1998, which is acontinuation-in-part of U.S. patent application Ser. No. 09/032,367,filed Feb. 27, 1998 (now U.S. Pat. No. 6,044,846) and acontinuation-in-part of U.S. patent application Ser. No. 09/921,356,filed Aug. 2, 2001, which is a continuation of U.S. patent applicationSer. No. 09/032,366, filed Feb. 27, 1998 (now abandoned).

FIELD OF THE INVENTION

[0002] This invention relates generally to an apparatus to treatsphincters, and more particularly to an apparatus to treat esophagealsphincters.

DESCRIPTION OF RELATED ART

[0003] Gastroesophageal reflux disease (GERD) is a commongastroesophageal disorder in which the stomach contents are ejected intothe lower esophagus due to a dysfunction of the lower esophagealsphincter (LES). These contents are highly acidic and potentiallyinjurious to the esophagus resulting in a number of possiblecomplications of varying medical severity. The reported incidence ofGERD in the U.S. is as high as 10% of the population (Castell D O;Johnston B T: Gastroesophageal Reflux Disease: Current Strategies ForPatient Management. Arch Fam Med, 5(4):221-7; (1996 April)).

[0004] Acute symptoms of GERD include heartburn, pulmonary disorders andchest pain. On a chronic basis, GERD subjects the esophagus to ulcerformation, or esophagitis and may result in more severe complicationsincluding esophageal obstruction, significant blood loss and perforationof the esophagus. Severe esophageal ulcerations occur in 20-30% ofpatients over age 65. Moreover, GERD causes adenocarcinoma, or cancer ofthe esophagus, which is increasing in incidence faster than any othercancer (Reynolds J C: Influence Of Pathophysiology, Severity, And CostOn The Medical Management Of Gastroesophageal Reflux Disease. Am JHealth Syst Pharm, 53(22 Suppl 3): S5-12 (Nov. 15, 1996)).

[0005] Current drug therapy for GERD includes histamine receptorblockers which reduce stomach acid secretion and other drugs which maycompletely block stomach acid. However, while pharmacologic agents mayprovide short term relief, they do not address the underlying cause ofLES dysfunction.

[0006] Invasive procedures requiring percutaneous introduction ofinstrumentation into the abdomen exist for the surgical correction ofGERD. One such procedure, Nissen fundoplication, involves constructing anew “valve” to support the LES by wrapping the gastric fundus around thelower esophagus. Although the operation has a high rate of success, itis an open abdominal procedure with the usual risks of abdominal surgeryincluding: postoperative infection, herniation at the operative site,internal hemorrhage and perforation of the esophagus or of the cardia.In fact, a recent 10 year, 344 patient study reported the morbidity ratefor this procedure to be 17% and mortality 1% (Urschel, J D:Complications Of Antireflux Surgery, Am J Surg 166(1):68-70; (1993July)). This rate of complication drives up both the medical cost andconvalescence period for the procedure and may exclude portions ofcertain patient populations (e.g., the elderly and immuno-compromised).

[0007] Efforts to perform Nissen fundoplication by less invasivetechniques have resulted in the development of laparoscopic Nissenfundoplication. Laparoscopic Nissen fundoplication, reported byDallemagne et al. Surgical Laparoscopy and Endoscopy, Vol. 1, No. 3,(1991), pp. 138-43 and by Hindler et al. Surgical Laparoscopy andEndoscopy, Vol. 2, No. 3, (1992), pp. 265-272, involves essentially thesame steps as Nissen fundoplication with the exception that surgicalmanipulation is performed through a plurality of surgical cannulaintroduced using trocars inserted at various positions in the abdomen.

[0008] Another attempt to perform fundoplication by a less invasivetechnique is reported in U.S. Pat. No. 5,088,979. In this procedure, aninvagination device containing a plurality of needles is insertedtransorally into the esophagus with the needles in a retracted position.The needles are extended to engage the esophagus and fold the attachedesophagus beyond the gastroesophageal junction. A remotely operatedstapling device, introduced percutaneously through an operating channelin the stomach wall, is actuated to fasten the invaginatedgastroesophageal junction to the surrounding involuted stomach wall.

[0009] Yet another attempt to perform fundoplication by a less invasivetechnique is reported in U.S. Pat. No. 5,676,674. In this procedure,invagination is done by a jaw-like device and fastening of theinvaginated gastroesophageal junction to the fundus of the stomach isdone via a transoral approach using a remotely operated fasteningdevice, eliminating the need for an abdominal incision. However, thisprocedure is still traumatic to the LES and presents the postoperativerisks of gastroesophageal leaks, infection and foreign body reaction,the latter two sequela resulting when foreign materials such as surgicalstaples are implanted in the body.

[0010] While the methods reported above are less invasive than an openNissen fundoplication, some still involve making an incision into theabdomen and hence the increased morbidity and mortality risks andconvalescence period associated with abdominal surgery. Others incur theincreased risk of infection associated with placing foreign materialsinto the body. All involve trauma to the LES and the risk of leaksdeveloping at the newly created gastroesophageal junction.

[0011] Besides the LES, there are other sphincters in the body which ifnot functioning properly can cause disease states or otherwise adverselyaffect the lifestyle of the patient. Reduced muscle tone or otherwiseaberrant relaxation of sphincters can result in a laxity of tightnessdisease states including but not limited to urinary incontinence.

[0012] There is a need to provide an apparatus to remodel a sphincter.Another need exists for an apparatus to deliver a polymer material intoa sphincter wall and deliver sufficient energy to the polymer materialto increase a wall thickness of the sphincter. There is a further needfor an apparatus to controllably reduce a diameter of a sphincterwithout creating a permanent impairment of the sphincter's ability toachieve a physiologically normal state of closure. Still a further needexists for an apparatus to deliver energy to a sphincter wall and createa tightening of a sphincter without permanently damaging anatomicalstructures near the sphincter. There is still another need for anapparatus to reduce the diameter of a lower esophageal sphincter toreduce a frequency of reflux of stomach contents into an esophagus.

SUMMARY OF THE INVENTION

[0013] One aspect of the invention provides a method for treating asphincter. The method provides a polymer material having a liquid state.The method also provides a catheter having a distal end, a tissuepiercing device carried by the distal end, and an energy delivery devicecoupled to the tissue piercing device. The tissue piercing device has alumen. The method introduces the catheter into an esophagus and piercesan exterior sphincter tissue surface within with the tissue piercingdevice. The method advances the tissue piercing device into an interiorsphincter tissue site and conveys the polymer material while in a liquidstate through the lumen into the interior sphincter tissue site. Themethod delivers energy to the tissue piercing device to transform thepolymer material into a less liquid state within the interior sphinctertissue site, to thereby remodel the sphincter.

[0014] In one embodiment, the method delivers energy to the tissuepiercing device to create controlled cell necrosis in the sphincter.

[0015] In one embodiment, the method provides a cooling medium andconveys the cooling medium into contact with the exterior sphinctertissue surface pierced by the tissue piercing device.

[0016] The polymer material can comprise, e.g., collagen or silicone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1A is an illustrated lateral view of the upper GI tractillustrating the positioning of the sphincter treatment apparatus of thepresent invention in the lower esophageal sphincter.

[0018]FIG. 1B is an illustrated lateral view of the upper GI tractillustrating the delivery of a polymer material into a treatment site inthe sphincter wall.

[0019]FIG. 2 is a lateral view of the present invention illustrating thecatheter lumen, catheter end energy delivery device, cable and powersupply.

[0020]FIG. 3 depicts a cross sectional view of sphincter anatomyillustrating the layers of the sphincter wall.

[0021]FIG. 4A is a lateral view of the RF electrode and sphincter wall,illustrating insulated and exposed electrode segments and the creationof a protected site.

[0022]FIG. 4B is a lateral view of the RF electrode and sphincter wall,illustrating apertures in the catheter which are used to control thepenetration angle of the tissue piercing device in a sphincter wall.

[0023]FIG. 5 is an enlarged lateral view illustrating the placement ofsensors on/adjacent the energy delivery device/RF electrode.

[0024]FIG. 6 is a cross sectional view illustrating the use of a fluidintroduction lumen and aperture in the energy delivery device/RFelectrode for delivery of a cooling medium.

[0025]FIG. 7 is a cross sectional view illustrating a visualizationdevice coupled to an embodiment of the invention.

[0026]FIG. 8 is a lateral view of the sphincter wall illustrating theuse of cooling medium to create cooled zones at the electrode-tissueinterface.

[0027]FIG. 9 depicts the flow path and fluid connections employed todeliver cooling medium to the energy delivery device/RF electrode and/orelectrode-tissue interface.

[0028]FIG. 10 is a flow chart illustrating a sphincter treatment method.

[0029]FIG. 11 is a lateral view of sphincter smooth muscle tissueillustrating electrical foci and electrically conductive pathways forthe origination and conduction of aberrant electrical signals in thesmooth muscle of the lower esophageal sphincter or other tissue.

[0030]FIG. 12 is a lateral view of a sphincter wall illustrating theinfiltration of tissue healing cells into a lesion in the smooth tissueof a sphincter following treatment with the sphincter treatmentapparatus of the present invention.

[0031]FIG. 13 is a view similar to that of FIG. 12 illustratingshrinkage of the lesion site caused by cell infiltration.

[0032]FIG. 14 is a lateral view of the esophageal wall illustrating thepreferred placement of lesions in the smooth muscle layer of anesophageal sphincter.

[0033]FIG. 15 is a lateral view illustrating a radial distribution ofcured polymer particles used to increase sphincter wall thickness anddecrease sphincter inner diameter.

[0034]FIG. 16 is a lateral view illustrating the use of a band of shrunkcollagen surrounding and mechanically supporting a radial distributionof cured polymer particles.

[0035]FIG. 17 depicts a block diagram of the feed back control systemthat can be used with the sphincter treatment apparatus.

[0036]FIG. 18 depicts a block diagram of an analog amplifier, analogmultiplexer and microprocessor used with the feedback control system ofFIG. 17.

[0037]FIG. 19 depicts a block diagram of the operations performed in thefeedback control system depicted in FIG. 17.

DETAILED DESCRIPTION

[0038] Referring now to FIGS. 1A, 1B and 2, one embodiment of asphincter treatment apparatus 10 delivers energy to a target tissue site12, also called treatment site 12, to produce cell necrosis 14 in asphincter 16, such as the lower esophageal sphincter (LES) . In thisembodiment, sphincter treatment apparatus 10 comprises a flexibleelongate shaft 18, also called introducer 18, or catheter 18, with adistal extremity 20, also called catheter end 20, in turn coupled withone or more energy delivery devices 22. Energy delivery devices 22 arecoupled to a guide wire 24 also called cable 24 and are also configuredto be coupled to a power source. Energy delivery device 22 is coupled toa tissue piercing device 26, which can also be the distal end 26 ofenergy delivery device 22. Energy delivery device 22 and tissue piercingdevice 26 may both have a continuous internal lumen 23 that isfluidically coupled to a fluid lumen 24′ in guide wire 24. Energydelivery device 22 and tissue piercing device 26 are configured topenetrate a fixed depth into a sphincter wall 28 and deliver energy to aportion thereof. In one embodiment tissue piercing device 26 is a hollowhypodermic needle 26 well known to those skilled in the art.

[0039] In one embodiment illustrated in FIG. 1B, tissue piercing device26 is configured to penetrate a fixed depth into a sphincter wall 28 anddeliver a polymer material 15 (also called polymer 15) via lumen 23 to atreatment site 12. Delivery of polymer 15 can be accomplished using aninfusion pump or syringe (neither shown but both well known to thoseskilled in the art) fluidically coupled to tissue piercing device 26.Upon delivery of sufficient thermal energy from energy delivery device22 to treatment site 12, the delivered polymer material 15′, undergoes acuring and/or polymerization reaction well known to those skilled in theart whereby one or more of the following occurs: (i) crosslinks formbetween adjacent molecular chains of polymer 15, (ii) the molecularchains of polymer 15 contract along their linear/longitudinal axisresulting in a shortening or shrinkage of polymer 15 in one or moreaxises, (iii) the molecular chains of polymer 15 increase in length (iv)a viscoelastic property of delivered polymer 15 is altered (v) theviscosity of delivered polymer 15′ is increased, and (vi) the stiffnessof delivered polymer 15 is increased. As a result of one or more ofthese changes, all or a portion of delivered polymer 15′ may undergo atransformation from a liquid or emulsion state to a less liquid orsemisolid state. The portion of delivered polymer 15′ that undergoesthis reaction is called cured polymer 15″ also called polymer particle15″. Suitable materials for polymer 15 include polysiloxanes (e.g.silicones), polyurethanes and collagen, all well known to those skilledin the art. Suitable geometries for polymer particle 15″ include, butare not limited to, the following shapes: spherical, semispherical, ovaland cylindrical. Suitable diameters for polymer particles 15″ include arange from 0.01 to 0.5 inches.

[0040] Referring to FIG. 2, catheter end 20 is configured to bepositionable in a sphincter 16 such as the LES or adjacent anatomicalstructure, such as the cardia of the stomach. Catheter 18 has sufficientlength to position catheter end 20 in the LES and/or stomach using atrans-oral approach. Typical lengths for catheter 18 include, but arenot limited to, a range of 40-180 cms. Suitable materials for catheter18 include, but are not limited to, polyethylenes, polyurethanes,silicones and other biocompatible polymers known to those skilled in theart. Energy delivery devices 22 can be in the form of needle electrodes,both solid or hollow, as is well known to those skilled in the art. Inother embodiments, energy delivery device 22 can be conical,cylindrical, rectangular or any polyhedron; each of said shapes having aflat, rounded, beveled, or pointed tip. Suitable materials for energydelivery device 22 include a combination of one or more of thefollowing: i) stainless and other steels suitable for electrodeapplications known to those skilled in the art, ii) alloys of gold,silver and platinum, iii) nickel-titanium alloys, or iv) otherconductors known to those skilled in the art.

[0041] Catheter 18 may have one or more lumens 30, that extend the frilllength of catheter 18, or only a portion thereof. Lumens 30 may be usedas paths for cables, catheters, guide wires, pull wires, insulatedwires, fluid and optical fibers. Lumens 30 may have one or moreapertures 30′ at or near distal catheter end 20. In one embodiment,lumens 30 (along with aperture 30′) in catheter 18 are used as a guidingpathway for guidewire 24 to facilitate the positioning of tissuepiercing device 26 at treatment site 12.

[0042] Guide wire 24 is configured to facilitate the positioning ofenergy delivery device 22 a selectable distance (1-4 mms) into thesphincter wall 28. Suitable materials and components for guide wire 24include an insulated wire, an insulated guide wire, a plastic-coatedstainless steel hypotube with internal wiring, or a catheter withinternal wiring, all of which are known to those skilled in the art.Guide wire 24 may also have one or more lumens 24′ which can be used todeliver fluid or gas. Also guide wire 24 may have one or more proximalfittings 24″ (such as a luer fitting or lemo connector) for facilitatingconnection to fluid lines and electronic cabling.

[0043] Turning now to a discussion of energy-tissue interactions, energyflowing through sphincter or other tissue causes heating of the tissuedue to absorption of the energy by the tissue. This heating can causeinjury to the affected cells and can be substantial enough to cause celldeath, a phenomenon also known as cell necrosis. The controlled deliveryof energy by energy delivery device 22 results in controlled cellnecrosis 14, also called lesions 14, at target tissue site 12.

[0044] Suitable energy devices and power sources for energy deliverydevice 22 include the following: (i) a radio-frequency (RF) sourcecoupled to an RF electrode, (ii) a coherent source of light coupled toan optical fiber, (iii) an incoherent light source coupled to an opticalfiber, (iv) a heated fluid coupled to a catheter with a closed channelconfigured to receive the heated fluid, (v) a heated fluid coupled to acatheter with an open channel configured to receive the heated fluid,(vi) a cooled fluid coupled to a catheter with a closed channelconfigured to receive the cooled fluid, (vii) a cooled fluid coupled toa catheter with an open channel configured to receive the cooled fluid,(viii) a cryogenic fluid, (ix) a resistive heating source, (x) amicrowave source providing energy from 915 MHz to 2.45 GHz and coupledto a microwave antenna, (xi) an ultrasound power source coupled to anultrasound emitter, wherein the ultrasound power source produces energyin the range of 300 KHZ to 3 GHz, or (xii) combinations of any of theabove. For ease of discussion for the remainder of this application, thepower source utilized is an RF source and energy delivery device 22 isone or more RF electrodes 22, also described as electrodes 22. However,all of the other herein mentioned power sources and energy deliverydevices are equally applicable to sphincter treatment apparatus 10.

[0045] Turning now to a discussion of sphincter anatomy (depicted inFIG. 3), the first several layers of sphincter 16 consist of a mucosallayer 32, a submucosal layer 33 and an underlying smooth muscle collagentissue layer 34. RF electrode 22 is configured to produce controlledcell necrosis or lesions 14 in smooth muscle collagen tissue layer 34underlying mucosal and submucosal layers 32 and 33. More specifically,RF electrode 22 is configured to produce controlled cell necrosis 14 inthe portion of smooth muscle collagen tissue 34′ that lies approximately1-4 nuns from the surface of mucosal layer 32.

[0046] Referring now to FIG. 4A, RF electrode 22 has an insulator 36,covering the exterior of an insulated segment 38 except for an exposedsegment 40. For purposes of this disclosure, an insulator is a barrierto either thermal or electromagnetic energy flow. As shown in FIG. 4A,insulated segment 38 is of sufficient length to extend into sphincterwall 28 and minimize the transmission of energy and subsequent injury toa protected site 42 near or adjacent to insulated segment 38. Typicallengths for insulated segment 38 include, but are not limited to, 1-4mms. Suitable materials for insulator 36 include, but are not limitedto, polytetrafluoroethylene (Teflon®, polyimides, polyamides and otherinsulating polymers known to those skilled in the art.

[0047] Referring now to FIG. 4B, in one embodiment lumens 30 andapertures 30′ are of sufficient diameter to allow the free movement ofguidewire 24 in catheter 18 so as to be able to controllably positiontissue piercing device 26 to a selected depth into sphincter wall 28.Apertures 30′ can be configured so as to control the angle ofpenetration 48 (also called penetration angle 48 or emergence angle 48)that tissue piercing device 26 makes with sphincter wall 28. Apertures30′ can be further configured so as to maintain penetration angle 48constant (or near constant) during the insertion of tissue piercingdevice 26 into sphincter wall 28 so as to minimize tearing orunnecessary trauma to sphincter wall tissue. In various embodiments, theemergence angle 48 of apertures 30′ which can vary from 1 to 90°.

[0048] Referring now to FIG. 5, one or more sensors 44 can be coupled toRF electrode 22 for sensing the temperature of sphincter tissue attarget tissue site 12. More specifically, sensors 44 permit accuratedetermination of the surface temperature of sphincter wall 28 at anelectrode tissue interface 46. This information can be used to regulateboth the delivery of energy and cooling medium to the interior surfaceof sphincter wall 28 as will be discussed herein. Sensors 44 can bepositioned on or adjacent to RF electrode 22. Suitable sensors that maybe used for sensor 44 include: thermocouples, fiber optics, resistivewires, thermocouple IR detectors, and the like. Suitable thermocouplesfor sensor 44 include: T type with copper constantene, J type, E typeand K types as are well known those skilled in the art.

[0049] Referring now to FIG. 6, RF electrode 22 includes a fluidintroduction lumen 23, that may be coupled with catheter lumen 30. Thesecoupled lumens provide a path for the delivery of a fluid, such as acooling or electrolytic fluid (which will be discussed herein), toelectrode tissue interface 46 or another site. As shown in FIG. 6, fluidintroduction lumen 23 may include an aperture 50 on the distal portionof RF electrode 22.

[0050] Referring now to FIG. 7, another embodiment of sphinctertreatment apparatus 10 includes a visualization device 52 which caninclude a combination of one or more of the following: a viewing scope,an expanded eyepiece, fiber optics (both imaging and illuminatingfibers), video imaging and the like.

[0051] It may be desirable to employ a cooling system 54 coupled toenergy delivery device 22 to cool all or a portion of energy-deliverydevice 22 and the area near electrode tissue interface 46 before, duringor after the delivery of energy in order to reduce the degree and areaof cell injury in the tissue adjacent electrode tissue interface 46. Asshown in FIG. 8, the use of cooling protects against, or otherwisereduces the degree of, cell damage to cooled zone 56 in the vicinity ofaperture 50 and/or electrode tissue interface 46 which will preferablyinclude mucosal and submucosal layers 32 and 33. In one embodiment shownin FIG. 9, cooling system 54 can include one or more of the following:i) a cooling medium 55 (which can be a liquid or a gas) that isdelivered to RF electrode 22 via aperture 50 and flow-controlled via afeedback control system 60 discussed herein, ii) a cooling mediumreservoir 58 coupled to aperture 50, and iii) a cooling device 59 (whichmay be integral to fluid reservoir 58) coupled to cooling medium 55 andcontrolled via a feedback control system 60 discussed herein. In anotherembodiment, cooling medium 55 can be introduced via apertures 50 orsemipermeable membranes located in one or more locations on sphinctertreatment apparatus 10 in communication with reservoir 58 and thermalcommunication with cooling device 59. In yet another embodiment, coolingmedium 55 can be introduced externally to RF electrode 22. In stillanother embodiment, cooling medium 55 is thermally coupled to RFelectrode 22 and/or electrode tissue interface 46. In yet anotherembodiment, cooling device 59 (such as a Peltier effect device or heatpipe) is thermally coupled to RF electrode 22 and/or electrode tissueinterface 46.

[0052]FIG. 10 is a flow chart illustrating a method for using sphinctertreatment apparatus 10. In this embodiment, sphincter treatmentapparatus 10 is first introduced into the esophagus under localanesthesia and positioned at target tissue site 12. Sphincter treatmentapparatus 10 can be introduced into the esophagus by itself or through alumen in an endoscope (not shown), such as disclosed in U.S. Pat. Nos.5,448,990 and 5,275,608, incorporated herein by reference, or a similaresophageal access device known to those skilled in the art.

[0053] The diagnostic phase of the procedure then begins and can beperformed using a variety of diagnostic methods, including, but notlimited to, the following: (i) visualization of the interior surface ofthe esophagus via an endoscope or other viewing apparatus inserted intothe esophagus, (ii) visualization of the interior morphology of theesophageal wall using ultrasonography to establish a baseline for thetissue to be treated, (iii) impedance measurement to determine theelectrical conductivity between the esophageal mucosal layers andsphincter treatment apparatus 10, and (iv) measurement and surfacemapping of the electropotential of the LES during varying time periodswhich may include such events as depolarization, contraction andrepolarization of LES smooth muscle tissue. This latter technique isdone to determine target tissue sites 12 in the LES or adjoininganatomical structures that are acting as electrical foci 107 orelectrically conductive pathways 109 for abnormal or inappropriatepolarization and relaxation of the smooth muscle of the LES (Refer toFIG. 11).

[0054] After diagnosis, the treatment phase of the procedure thenbegins. In this phase of the procedure the delivery of energy to targettissue site 12 can be conducted under feedback control (describedherein), manually or by a combination of both. Feedback control enablessphincter treatment apparatus 10 to be positioned and retained in theesophagus during treatment with minimal attention by the physician.Feedback can be included and is achieved by the use of one or more ofthe following methods: (i) visualization, (ii) impedance measurement,(iii) ultrasonography, (iv) temperature measurement and, (v) sphinctercontractile force measurement via manometry. A second diagnostic phasemay be included after the treatment is completed. This provides anindication of LES tightening treatment success, and whether or not asecond phase of treatment, to all or only a portion of the esophagus,now or at some later time, should be conducted. The second diagnosticphase is accomplished through, (i) visualization, (ii) measuringimpedance, (iii) ultrasonography, (iv) temperature measurement, or (v)measurement of LES tension and contractile force via manometry. It willbe appreciated that the above procedure is applicable in whole or partto the treatment of other sphincters in the body.

[0055] The area and magnitude of cell injury in the LES or sphincter 16can vary. However, it is desirable to deliver sufficient energy to thetargeted tissue site 12 to be able to achieve tissue temperatures in therange of 55-95° C. and produce lesions 14 at depths ranging from 14 mmsfrom the interior surface of the LES or sphincter wall 28. It is alsodesirable to deliver sufficient energy such that the resulting lesions14 have a sufficient magnitude and area of cell injury to cause aninfiltration and/or proliferation of lesion 14 by fibroblasts 110,myofibroblasts 112, macrophages 114 and other cells involved in thetissue healing process (refer to FIG. 12). As shown in FIG. 13, thesecells cause a contraction of tissue around lesion 14, decreasing itsvolume and/or altering the biomechanical properties at lesion 14 so asto result in a tightening of LES or sphincter 16. These changes arereflected in transformed lesion 14′ shown in FIG. 13.

[0056] It is desirable that lesions 14 are predominantly located in thesmooth muscle collagen layer of selected sphincter 16 at the depthsranging from 1 to 4 mms from the interior surface of sphincter wall 28.

[0057] Accordingly, the diameter of lesions 14 can vary between 0.1 to 4mms. It is preferable that lesions 14 are less than 4 mms in diameter inorder to reduce the risk of thermal damage to the mucosal layer. In oneembodiment, a 2 mm diameter lesion 14 centered in the wall of the smoothmuscle collagen layer provides a 1 mm buffer zone to prevent damage tothe mucosa, submucosa and adventitia, while still allowing for cellinfiltration and subsequent sphincter tightening on approximately 50% ofthe thickness of the wall of the smooth muscle collagen layer (refer toFIG. 14). Also, lesions 14 can vary both in number and position withinsphincter wall 28. Once treatment is completed, sphincter treatmentapparatus 10 is withdrawn from the esophagus or other sphincter 16. Thisresults in the LES or other sphincter returning to approximately itspretreatment state and diameter.

[0058] Referring now to FIG. 15, in one embodiment polymer particles 15″can be distributed in a variety of patterns in sphincter wall 28including a radial distribution at even depths along a radial axis ofsphincter 16. Other distributions not shown include: (i) a wavy orfolded circle of polymer particles 15″ at varying depths in sphincterwall 28 evenly spaced along the radial axis of sphincter 16, (ii)polymer particles 15″ randomly distributed at varying depths, but evenlyspaced in a radial direction; and, (iii) an eccentric pattern of polymerparticles 15″ in one or more radial locations in sphincter wall 28. Thepattern of and diameter of polymer particles 15″ can be selected tocontrollably increase the thickness 28′ of sphincter wall 28 and/ordecrease the inner diameter 16′ of sphincter 16.

[0059] Referring now to FIG. 16, RF energy can be delivered to sphincterwall 28 to shrink native collagen 51 within the smooth muscle collagentissue layer 34 of sphincter wall 28 so as to create a supporting band57 of tightened collagen in contact with one or more of polymerparticles 15″ distributed along a radial axis of sphincter 16. Band 57serves to both mechanically link and mechanically support polymerparticles 15″. This serves one or more of-the following functions: (i)distribution of the stresses within sphincter wall 28, (ii) retention ofthe desired placement of polymer particles 15″ within sphincter wall 28;and, (iii) maintenance of improvements in the tension and inner diameterof sphincter wall 28. Also band 57 can be selectively shrunk so as toselectively tighten sphincter 16 and decrease inner sphincter diameter16′. In another embodiment, band 57 can be composed of fibroblasts 110,myofibroblasts 112 and other tissue healing cells.

[0060] In one embodiment, elements of sphincter treatment apparatus 10are coupled to an open or closed loop feedback control system 60.Referring now to FIG. 17, an open or closed loop feedback system 60couples sensor 346 to energy source 392. In this embodiment, electrode314 is one or more RF electrodes 314. The temperature of the tissue, orof RF electrode 314, is monitored, and the output power of energy source392 adjusted accordingly. The physician can, if desired, override theclosed or open loop system 60. A microprocessor 394 can be included andincorporated in the closed or open loop system to switch power on andoff, as well as modulate the power. The closed loop system 60 utilizesmicroprocessor 394 to serve as a controller, monitor the temperature,adjust the RF power, analyze the result, refeed the result, and thenmodulate the power.

[0061] With the use of sensor 346 and feedback control system 60, tissueadjacent to RF electrode 314 can be maintained at a desired temperaturefor a selected period of time without causing a shut down of the powercircuit to electrode 314 due to the development of excessive electricalimpedance at electrode 314 or adjacent tissue as is discussed herein.Each RF electrode 314 is connected to resources which generate anindependent output. The output maintains a selected energy at RFelectrode 314 for a selected length of time.

[0062] Current delivered through RF electrode 314 is measured by currentsensor 396. Voltage is measured by voltage sensor 398. Impedance andpower are then calculated at power and impedance calculation device 400.These values can then be displayed at user interface and display 402.Signals representative of power and impedance values are received by acontroller 404.

[0063] A control signal is generated by controller 404 that isproportional to the difference between an actual measured value, and adesired value. The control signal is used by power circuits 406 toadjust the power output an appropriate amount in order to maintain thedesired power delivered at respective RF electrodes 314.

[0064] In a similar manner, temperatures detected at sensor 346 providefeedback for maintaining a selected power. Temperature at sensor 346 isused as a safety means to interrupt the delivery of power when maximumpre-set temperatures are exceeded. The actual temperatures are measuredat temperature measurement device 408, and the temperatures aredisplayed at user interface and display 402. A control signal isgenerated by controller 404 that is proportional to the differencebetween an actual measured temperature and a desired temperature. Thecontrol signal is used by power circuits 406 to adjust the power outputan appropriate amount in order to maintain the desired temperaturedelivered at the sensor 346. A multiplexer can be included to measurecurrent, voltage and temperature, at the sensor 346, and energy can bedelivered to RF electrode 314 in monopolar or bipolar fashion.

[0065] Controller 404 can be a digital or analog controller, or acomputer with software. When controller 404 is a computer it can includea CPU coupled through a system bus. This system can include a keyboard,a disk drive, or other non-volatile memory systems, a display, and otherperipherals, as are known in the art. Also coupled to the bus is aprogram memory and a data memory.

[0066] User interface and display 402 includes operator controls and adisplay. Controller 404 can be coupled to imaging systems including, butnot limited to, ultrasound, CT scanners, X-ray, MRI, mammographic X-rayand the like. Further, direct visualization and tactile imaging can beutilized. The output of current sensor 396 and voltage sensor 398 areused by controller 404 to maintain a selected power level at RFelectrode 314. The amount of RF energy delivered controls the amount ofpower. A profile of the power delivered to electrode 314 can beincorporated in controller 404 and a preset amount of energy to bedelivered may also be profiled.

[0067] Circuitry, software and feedback to controller 404 result inprocess control, the maintenance of the selected power setting which isindependent of changes in voltage or current, and is used to change thefollowing process variables: (i) the selected power setting, (ii) theduty cycle (e.g., on-off time), (iii) bipolar or monopolar energydelivery; and, (iv) fluid delivery, including flow rate and pressure.These process variables are controlled and varied, while maintaining thedesired delivery of power independent of changes in voltage or current,based on temperatures monitored at sensor 346.

[0068] Referring now to FIG. 18, current sensor 396 and voltage sensor398 are connected to the input of an analog amplifier 410. Analogamplifier 410 can be a conventional differential amplifier circuit foruse with sensor 346. The output of analog amplifier 410 is sequentiallyconnected by an analog multiplexer 412 to the input of A/D converter414. The output of analog amplifier 410 is a voltage which representsthe respective sensed temperatures. Digitized amplifier output voltagesare supplied by A/D converter 414 to microprocessor 394. Microprocessor394 may be a type 68HCII available from Motorola. However, it will beappreciated that any suitable microprocessor or general purpose digitalor analog computer can be used to calculate impedance or temperature.

[0069] Microprocessor 394 sequentially receives and stores digitalrepresentations of impedance and temperature. Each digital valuereceived by microprocessor 394 corresponds to different temperatures andimpedances.

[0070] Calculated power and impedance values can be indicated on userinterface and display 402. Alternatively, or in addition to thenumerical indication of power or impedance, calculated impedance andpower values can be compared by microprocessor 394 to power andimpedance limits. When the values exceed predetermined power orimpedance values, a warning can be given on user interface and display402, and additionally, the delivery of RF energy can be reduced,modified or interrupted. A control signal from microprocessor 394 canmodify the power level supplied by energy source 392.

[0071]FIG. 19 illustrates a block diagram of a temperature and impedancefeedback system that can be used to control the delivery of energy totissue site 416 by energy source 392 and the delivery of cooling medium55 to electrode 314 and/or tissue site 416 by flow regulator 418. Energyis delivered to RF electrode 314 by energy source 392, and applied totissue site 416. A monitor 420 ascertains tissue impedance, based on theenergy delivered to tissue, and compares the measured impedance value toa set value. If measured impedance is within acceptable limits, energycontinues to be applied to the tissue. However if the measured impedanceexceeds the set value, a disabling signal 422 is transmitted to energysource 392, ceasing further delivery of energy to RF electrode 314.

[0072] The control of cooling medium 55 to electrode 314 and/or tissuesite 416 is done in the following manner. During the application ofenergy, temperature measurement device 408 measures the temperature oftissue site 416 and/or RF electrode 314. A comparator 424 receives asignal representative of the measured temperature and compares thisvalue to a pre-set signal representative of the desired temperature. Ifthe measured temperature has not exceeded the desired temperature,comparator 424 sends a signal to flow regulator 418 to maintain thecooling solution flow rate at its existing level. However if the tissuetemperature is too high, comparator 424 sends a signal to a flowregulator 418 (connected to an electronically controlled micropump, notshown) representing a need for an increased cooling solution flow rate.

[0073] The foregoing description of a preferred embodiment of theinvention has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in this art. Itis intended that the scope of the invention be defined by the followingclaims and their equivalents.

What is claimed is:
 1. A method for treating a sphincter comprising thesteps of providing a polymer material having a liquid state, providing acatheter having a distal end, a tissue piercing device carried by thedistal end, the tissue piercing device having a lumen, and an energydelivery device coupled to the tissue piercing device, introducing thecatheter into an esophagus, piercing an exterior sphincter tissuesurface within with the tissue piercing device, advancing the tissuepiercing device into an interior sphincter tissue site, conveying thepolymer material while in a liquid state through the lumen into theinterior sphincter tissue site, delivering energy to the tissue piercingdevice to transform the polymer material into a less liquid state withinthe interior sphincter tissue site, to thereby remodel the sphincter. 2.A method according to claim 1 further including the step of deliveringenergy to the tissue piercing device to create controlled cell necrosisin the sphincter.
 3. A method according to claim 1 or 2 furtherincluding the steps of providing a cooling medium, and conveying thecooling medium into contact with the exterior sphincter tissue surfacepierced by the tissue piercing device.
 4. A method according to claim 1or 2 wherein the polymer material comprises collagen.
 5. A methodaccording to claim 1 or 2 wherein the polymer material comprisessilicone.